Ropinirole is a dopamine agonist and having selective affinity for dopamine D2-like receptors and little or no affinity for non-dopaminergic brain receptors. Ropinirole is indicated as adjunct therapy to levodopa in patients with advanced Parkinson's disease. Also, recent clinical trials have focused on its use, as monotherapy in patients with early Parkinson's disease
Ropinirole was first reported in U.S. Pat. No. 4,452,880. It discloses the process for the preparation of Ropinirole hydrochloride as shown in following Scheme-1

The process as shown above comprises conversion of 2-methyl-3-nitro phenyl acetic acid (II) with thionyl chloride to 2-Methyl-3-nitro-phenylacetyl chloride (III), which upon reaction with Di-n-propyl amine (DPA) gives 2-Methyl-3-nitro phenyl-N,N-di-n-propyl acetamide (IV) in syrup form. This intermediate (IV) is further reduced with Borane/THF and subsequent treatment with HCl/NaOH to give 2-Methyl-3-nitro phenyl ethyl-N,N-di-n-propyl amine (V). Further, compound (V) is treated with Na metal, Ethanol and diethyl oxalate to obtain Ethyl 6-(2-di-n-propylaminoethyl)-2-nitrophenyl pyruvate (VI), which is further treated with hydrogen peroxide , NaOH and HCl and converted to 6-(2-Di-n-propylaminoethyl)-2-nitro phenyl acetic acid hydrochloride (VII). This intermediate is reduced with palladium/carbon to give Ropinirole hydrochloride (Ia).
Alternative process for the preparation of Ropinirole is described in J. Med. Chem. 1985, 28, 1533-1536 as shown in Scheme-2. The process comprises, the reduction 2-Methyl-3-nitro-benzoic acid (VIII) with diborane to carbinol of formula (IX). The carbinol compound (IX) is chlorinated with thionyl chloride in pyridine to give highly lachrymatory compound of formula (X), which is further converted to compound of formula (XII) by reaction with Potassium cyanide and followed by hydrolysis. 2-methyl-3-nitrophenyl acetic acid (XII) is converted to its acid chloride with thionyl chloride and treated with Di-n-propylamine to give 2-Methyl-3-nitrophenyl-N,N-di-n-propyl acetamide of formula (IV). The compound of formula (IV) is further reduced with borane in THF under reflux to give 2-Methyl-3-nitrophenylethyl-N,N-di-n-propyl amine (V). The amine of formula (V) is reacted with potassium metal in Ethanol and diethyl oxalate resulting in compound (VI) (where R=H), which is treated with hydrogen peroxide, NaOH and HCl to give the intermediate 2-Nitro-6-(2-di-n-propylaminoethyl)-phenyl acetic acid hydrochloride of formula (VII). This intermediate is hydrogenated on palladium/carbon in ethanol to give desired compound Ropinirole hydrochloride of formula (Ia)

However, the above described process suffers with the following drawbacks:                (i) 2-Methyl-3-nitro benzyl chloride of formula (X) is highly lachrymator and very difficult to handle at commercial production        (ii) The reduction of 2-Methyl-3-nitro benzoic acid (VIII) is carried out with borane/THF, which is highly flammable and hazardous for handling in an industrial scale.        (iii) It involves the use of potassium cyanide in the cynation reaction for the preparation of 2-Methyl-3-nitro benzyl cyanide. Potassium cyanide is highly toxic substance and requires special precaution for its use in production. It is highly desirable to avoid such toxic material.        (iv) Also, this process gives lower yield        (v) Additionally, isolation of intermediate compound of formula (V) as described in Scheme 1 requires the use of Kugelrohr apparatus. Use of such apparatus for commercial production is not feasible.        
Overall, the process for the preparation of Ropinirole hydrochloride described in the prior art having disadvantage with respect to the use of toxic, lachrymator material and special apparatus in the process. Also, it gives lower yield. Hence, the process is not feasible for commercial production. So, there is a need for the process for the preparation of Ropinirole hydrochloride, which is easy to handle, suitable for commercial production and obviates the shortcomings of the known processes.